DE10350460B4 - Method for producing semiconductor devices having micromechanical and / or microelectronic structures, which result from the fixed connection of at least two semiconductor wafers, and corresponding arrangement - Google Patents

Abstract

method for the production of micromechanical and / or microelectronic Structured semiconductor devices by solid bonding arise from at least two semiconductor wafers, wherein the one Type of semiconductor wafers, referred to as system disk (1, 8) is involved, micro-mechanical and microelectronic structures and the other type, referred to as cover plate (2), at least electronic Structures carries and system disk (1, 8) and cover disk (2) have locations, in which electrically conductive areas as contact areas on the to be joined surfaces the semiconductor wafers are present, to which a fixed electrical Connection is made, characterized in that the haüptsächlich mechanically carrying connection of the discs by low-melting, electric insulating glass solders (6) and the also mechanically solid electrical Combination of low-melting, electrically conductive glass solders (5), wherein the solder paste for the only mechanically bearing firm connection at least in annular closed areas (6), the hermetic after the connection of the semiconductor wafers closed cavities form, and the solder paste (5) for the electric ...

Description

The The invention is based on a method for connecting processed Semiconductor wafers by means of electrically conductive and electrically insulating structured Intermediate interconnection layers according to the preamble of claim 1.

The Connecting processed semiconductor wafers is in production used by microelectronic and microelectromechanical systems, to cover certain structures by a cap already in the disk process. This operation is firstly necessary to sensitive mechanical Structures during subsequent processing steps to protect or the actual encapsulation of the individual elements, e.g. optical components, already in the disk association make and thus allow special structures. Usual methods for joining from e.g. System and cover discs are anodic and direct bonding, and the bonding by means of low-melting glass intermediate layers (Glass frit bonding). there are usually the mechanical or electrically active Elements on the system disk. The cover disk, however, usually serves only as a protective cover and has the state of the art no or only a few electrical structures. The bonding methods listed above have the property that the Disks are not conductively connected. This is on the one hand, that the Cover disc itself is not conductive (anodic bonding). On the other hand Bonding intermediate layers are not conductive (Bondoxid for direct bonding, glass interlayer for glass-frit bonding). However, when using encapsulation bonding, it is usually necessary to targeted the entire lid or structures on the lid electrically conductively connect. An electrical connection of the entire lid is z.T. necessary to bring it to a certain potential, e.g. Mass, to lay. For The readout of capacitive sensors are evaluation electrodes on the Lid necessary, which must be contacted to the system disk out to a wire bonding during to enable the set-up and connection process in one level. To increase The packing density of microsystems, it is advantageous Auswerteschaltungen to integrate on the cover disk, if this to the system disk can be contacted electrically. So far, only electrical disc-to-disc contacts of known anodic bonding. This metallization of the brought to be bonded discs in mechanical contact and through the resulting disc connection force is firmly compressed (KADAR, Z., BOSSCHE, A., MOLLINGER, J., Sensors & Actuators A Vol. 52 (1996), p. 151-155 - aluminum press-on contacts for glass to silicon anodic bonding). This method however, has two serious disadvantages. For one disturb the electrical contact areas the formation of the actual Scheibenbondverbindung. On the other hand, there is no material connection in the field of electrical Contacts, so that their reliability is therefore questionable. As the most universal disc bonding method for encapsulation purposes the glass-frit bonding, since it provides very high bond yields and due to the planarizing effect of the molten glass interlayer surface profiles compensates for the discs to be joined and thus lateral metallic Vias enabled in the bond interface.

In the DE 196 16 014 A1 describes a method for producing semiconductor devices having micromechanical structures, in which the micromechanical structures are produced in a separate semiconductor wafer and this semiconductor wafer is applied with the interposition of a connecting element to a second semiconductor wafer having the integrated circuit.

This Connecting element causes additional effort, thus increasing the cost and has a negative impact on the reliability of the device.

Of the Invention is based on the object, the connection method of Micromechanical and electronic structures bearing semiconductor wafers so that a fixed and re cavities tight closing Connection of the semiconductor wafers with simultaneous solid electrical Connection of the discs without the extra effort of an extra Connection element is given.

Is solved the task with the in the characterizing part of claims 1, 9 and 12 specified characteristics.

Of the The subject matter of claim 1 has the advantages that the combination of conductive and insulating glass structures in glass frit bonding in a simplified way possible makes it possible to connect the semiconductor wafers in one operation and targeted areas of interconnected slices electrically with a fixed contact connection without a separate connection element to join.

The invention is particularly suitable for microelectromechanical structures that are integrated with structures of the evaluation. In addition, more than two semiconductor slides ben stacked together.

advantageous Embodiments of the subject matter of claims 1, 9 and 12 are in the dependent claims specified.

The Invention will now be described with reference to an embodiment with two semiconductor wafers explained with the aid of the drawings. Show it

1 a system disk ( 1 ), with a cover disc ( 2 ) was connected according to the inventive method in a schematic sectional view,

2 the top view of an arrangement as shown in 1 is shown

3 a variant of the inventive conductive connection between the system disk ( 1 ) and cover disc ( 2 ).

As in 1 show the low-melting structured insulating glass intermediate layer ( 6 ) and the electrically conductive glass-based solder ( 5 ) the system disk ( 1 ) with the cover disc ( 2 ), wherein at the same time a selective contacting of the cover plate ( 2 ) to the system disk ( 1 ), or between electrically active structures of both discs is made. According to the method, the application and premelting of the two glass solders can be separated and carried out in succession. But also sequential application and a common pre-melting are possible. In the bonding process, the conductive and non-conductive disk connections are then formed simultaneously. For this, the processing temperatures of the two glasses used must be within the same range. In the area of the non-conductive glass solder, metallic interconnects ( 4 ), which are located on the system disk ( 1 ) and by an intermediate insulator ( 7 ) are isolated to the substrate, are embedded. This allows the low-resistance connection of the structures to be protected by the cover ( 3 ). At the same time, the structures to be covered can be hermetically sealed. The mainly mechanically bearing disc connection is through the glass solder ( 6 ), since this is very well adapted in its thermal expansion to silicon. The electrical contact surfaces must be kept small in order to minimize mechanical stresses. Are used as system disks SOI disks ( 8th ) (silicon-on-insulator) used as in 3 shown, it is possible via the conductive glass solder ( 5 ) the substrate ( 11 ) electrically connect the SOI disc. For this the active layer ( 9 ) of the SOI substrate and the buried oxide ( 10 ) in the appropriate place, so that the electrically conductive solder glass ( 5 ) can flow into the opening and thus contact the carrier disk. Only the desired locations of the active semiconductor layer ( 9 ) must connect the semiconductor layer ( 9 ) are isolated on the hole walls. {The necessary intermediate insulator ( 7 ), please refer 1 , is in 3 not shown.} Since the common SOI-based technologies contain these sub-steps, there is no additional effort.

• – Siebdruck zum Aufbringen der elektrisch nicht leitenden Glaspaste auf die Deckscheibe
• – Konditionieren und Vorschmelzen des elektrisch nicht leitenden Glases
• – Siebdruck zum Aufbringen der elektrisch leitenden Glaspaste auf die Deckscheiben
• – Konditionieren und Vorschmelzen des elektrisch leitenden Glases
• – Ausrichten von System- und Deckscheibe
• – Bonden unter mechanischem Druck bei der Verarbeitungstemperatur der Gläser

Alternativ kann das Aufbringen der Gläser auch in umgekehrter Reihenfolge bzw. auf die Systemscheibe erfolgen.If the design of the system disk and the cover disk takes into account the corresponding electrical contact surfaces and necessary disk connection frames, the following process, for example, is possible for producing the electrically conductive and insulating disk connections:

• - Screen printing for applying the electrically non-conductive glass paste on the cover plate
• - Conditioning and premelting of the electrically non-conductive glass
• - Screen printing for applying the electrically conductive glass paste on the cover plates
• - Conditioning and pre-melting of the electrically conductive glass
• - Aligning the system and cover disk
• - Bonding under mechanical pressure at the processing temperature of the glasses

Alternatively, the application of the glasses can also be done in reverse order or on the system disk.

1

system disc with microelectromechanical or with

electronic structures

2

Cover plate, e.g. also provided with electronic structures

3

to protective microelectromechanical or electronic

structures

4

Metal structures Feeders and Bonding Pads

5

electrical conductive connection glass

6

electrical insulating connecting glass

7

Interlayer insulation film

8th

SOI wafers (silicon on insulator)

9

active electronic structures supporting silicon layer (active

Layer)

10

buried oxide

11

carrier disc (Substrate)

12

Isolation trenches in active layer

Claims (14)

Process for the production of semiconductor devices having micromechanical and / or microelectronic structures, which are protected by the solid Connecting at least two semiconductor wafers are produced, wherein one type of semiconductor wafers serving as a system disk ( 1 . 8th ), micromechanical and microelectronic structures and the other type, which serves as a cover plate ( 2 ), carries at least electronic structures and system disk ( 1 . 8th ) and cover disc ( 2 ) Have locations in which electrically conductive areas are present as contact areas on the surfaces to be joined of the semiconductor wafers, on which a solid electrical connection is made, characterized in that the mechanically mechanically supporting connection of the panes by low-melting, electrically insulating glass solders ( 6 ) and the likewise mechanically strong electrical connection of low-melting, electrically conductive glass solders ( 5 ), wherein the solder paste for the only mechanically bearing solid connection at least in annular closed areas ( 6 ), which form the hermetically sealed cavities after the connection of the semiconductor wafers, and the solder paste ( 5 ) are applied to one or both of the sides of the pane to be bonded locally to match the locations where electrical contact areas are present on the surfaces to be joined such that spaces remain between the two different glasses after fusing and after the conditioning and premelting the connection under mechanical pressure at the processing temperature of the glasses takes place. Process according to Claim 1, characterized in that the glass solder pastes ( 5 . 6 ) are applied by screen printing. Process according to Claim 1, characterized in that the non-conductive, low-melting glass solder ( 6 ) and the electrically conductive glass solder ( 5 ) have different conditioning and Vorschmelzbedingungen and therefore the conditioning and pre-melting is carried out sequentially in separate processes. Process according to Claim 1, characterized in that the non-conductive, low-melting glass solder ( 6 ) and the electrically conductive glass solder ( 5 ) have the same processing temperature. Process according to Claim 1, characterized in that the non-conductive, low-melting glass solder ( 6 ) and the electrically conductive glass solder ( 5 ) have different processing temperatures and these are passed through in a process in succession. Method according to one of the preceding claims, characterized in that at least one of the discs ( 1 . 11 ) is electrically connected in its electronically unstructured area (starting material area). Method according to one of the preceding claims, characterized in that the connection formations of the glass solders ( 5 . 6 ) at temperatures less than 450 degrees Celsius. Method according to one of the preceding claims, characterized in that the system disk comprises an SOI disk ( 8th ) and the electrical connection of the substrate of the SOI disc ( 11 ) across the bonding surfaces through previously created openings in the active silicon layer ( 9 ) and in the buried oxide layer ( 1 ) carried out with electrically conductive glass solder ( 5 ) are filled, wherein the wall portions of the openings in the active silicon layer before the electrical connection, if necessary, provided with an insulating layer. Micromechanical and microelectronic structures having semiconductor device, which is produced by connecting at least two semiconductor wafers prior to separation of the wafer assembly, wherein a type of semiconductor wafers serving as a system disk ( 1 . 8th ), micromechanical and microelectronic structures and the other type, which serves as a cover plate ( 2 ), carries at least electronic structures and system disk ( 1 . 8th ) and cover disc ( 2 ) Have contact points in which electrically conductive regions are present on the connected surfaces of the semiconductor wafers, to which there is a firm electrical connection, characterized in that the mechanically mechanically supporting connection of the wafers by low-melting, electrically insulating glass solder ( 6 ) and the electrical connection by low-melting, electrically conductive glass solder ( 5 ), wherein the electrically insulating glass solder ( 6 ) at least in annular closed areas which form hermetically sealed cavities and the glass solder for the electrically conductive connections locally bounded at the locations where the disks are electrically contacted ( 5 ) and the different glass solders are separated by a glass-free region. Semiconductor component according to Claim 9, characterized in that the glass solders ( 5 . 6 ) to those with melting temperatures less than 450 degrees Celsius. Semiconductor component according to Claim 9 or 10, characterized in that at least one of the semiconductor wafers comprises an SOI wafer ( 8th ) and an additional electrical connection of the substrate ( 11 ) of the SOI disc ( 8th ) with the adjacent disc ( 2 ) exists across the bonding surfaces, which passes through with electrically conductive glass lot ( 5 ) filled openings in the active silicon layer ( 9 ) and in the buried oxide layer ( 10 ), wherein the wall portions of the opening in the active silicon layer are provided with an insulating layer. Semiconductor device having microelectronic structures, which is formed by connecting at least two semiconductor wafers, wherein on all semiconductor wafers microelectronic structures are formed and have these locations in which electrically conductive regions, on the joined surfaces of the semiconductor wafers are present as contact areas with the electronic Structures are interconnected and on which solid electrical connections between the semiconductor wafers are made, characterized in that the semi-mechanically mechanically carrying connection of the semiconductor wafers by low-melting electrically insulating glass solder ( 6 ) and the electrical connections by low-melting electrically conductive glass solder ( 5 ), wherein the glass solder ( 5 ) is present for the electrically conductive connections locally limited at the contact points and a gap between the different glass solders ( 5 ) is available. Semiconductor component according to Claim 12, characterized that it the glass solders are smaller with those with melting temperatures than 450 degrees Celsius. Semiconductor component according to Claim 12 or 13, characterized in that at least one of the semiconductor wafers comprises an SOI disk ( 8th ) and there is an additional electrical connection of the substrate of the SOI disc with the adjacent disc across the connection surfaces, which passes through with electrically conductive solder glass (US Pat. 5 ) filled openings in the active silicon layer ( 9 ) and in the buried oxide layer ( 10 ), wherein the wall regions of the opening in the active silicon layer ( 9 ) are provided with an insulating layer.